On 01/31/2012 01:48 PM, Andrew Dunstan wrote:
On 01/31/2012 01:32 PM, Merlin Moncure wrote:
On Tue, Jan 31, 2012 at 12:15 PM, Josh Berkus<j...@agliodbs.com> wrote:
Andrew,
based on Abhijit's feeling and some discussion offline, the consensus
seems to be to remove query_to_json.
If we do that, what would getting complete query results back from a
query look like? It's important to make this as simple for developers
as possible.
two options:
1. row_to_json(rowvar)
SELECT row_to_json(foo) from foo;
SELECT row_to_json(row(a,b,c)) from foo;
2. array_to_json(array_agg()/array())
SELECT array_to_json(array(select foo from foo));
SELECT array_to_json(array[1,2,3]);
#1 I expect will be the more used version -- most json handling client
side api (for example node.js drivers) are optimized for row by row
processing, but via #2 you can stuff a whole query into single json
object if you're so inclined.
You could also write a wrapper something like this:
create function query_to_json(qtext text) returns json language
plpgsql as
$$
begin
return query execute 'select array_to_json(array(' || qtext ||
'))';
end;
$$;
The array(select...) locution turns out to have less flexibility than
the array_agg(record-ref) locution.
Anyway, for those playing along, I have removed query_to_json, and added
optional pretty printing to array_to_json and row_to_json. WIP can be
seen at <https://bitbucket.org/adunstan/pgdevel>. I still have docs and
output function caching to do, and should post a revised patch within
the next 48 hours.
cheers
andrew
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